Circuit mounting unit

Abstract

The present invention relates to a circuit mounting unit that can prevent a voltage drop and noise occurrence due to current inflow at the time of a hot insertion or withdrawal operation without mounting a capacitor with large capacitance on the side of a main unit. The circuit mounting unit includes a first voltage control unit that controls to increase gradually a voltage supplied to a load voltage converter from the main unit side to a predetermined voltage when the circuit mounting unit is exchangeably inserted into or pulled out of the main unit without halting electric power supplied from the main unit. The circuit mounting unit is mounted onto a printed wiring board on which various elements such as ICs and LSIs are previously mounted to form a predetermined circuit.

What is claimed is: 
     
       1. A circuit mounting unit, comprising: a first element connected to a main unit via a connector, driven by a first voltage which is supplied from said main unit;   a load voltage converter for converting said first voltage from said main unit into a second voltage different from said first voltage;   a second element driven by said second voltage converted by said load voltage converter; and   a first voltage control unit for boosting gradually a voltage supplied from said main unit to said load voltage converter into said first voltage when an insertion operation to said main unit is performed without halting a power supply from said main unit,   said first control unit including: a variable resistor that varies from a high resistance state thereof to a low resistance state thereof as a switching voltage externally added increases,   a switching voltage converter that converts an electric power from said main unit into said switching voltage to supply to said variable resistor, and   a capacitor inserted between an output terminal from said switching voltage of said switching voltage converter and a ground line,   said variable resistor in said first voltage control unit being connected to a power supply line from said main unit to said load voltage converter.     
     
     
       2. The circuit mounting unit according to claim 1, wherein said variable resistor in said first voltage control unit comprises an N-channel field effect transistor. 
     
     
       3. The circuit mourning unit according to claim 2, further comprising a resistor which is connected in parallel to said capacitor in said first voltage control unit. 
     
     
       4. The circuit mounting unit according to claim 3, wherein said variable resistor and said switching voltage convertor are previously formed in an integrated circuit form. 
     
     
       5. The circuit mounting unit according to claim 2, wherein said variable resistor and said switching voltage converter which constitute said first voltage control unit are previously formed in an integrated circuit form. 
     
     
       6. The circuit mounting unit according to claim 1, further comprising a resistor which is connected in parallel to said capacitor in said first voltage control unit. 
     
     
       7. The circuit mounting unit according to claim 6, wherein said variable resistor and said switching voltage converter are previously formed in an integrated circuit form. 
     
     
       8. The circuit mounting unit according to claim 1, wherein said variable resistor and said switching voltage converter which constitute said first voltage control unit are previously formed in an integrated circuit form. 
     
     
       9. A circuit mounting unit, comprising: a first element connected to a main unit via a connector, driven by a first voltage which is supplied from said main unit;   a load voltage converter for converting said first voltage from said main unit into a second voltage different from said first voltage;   a second element driven by said second voltage converted by said load voltage converter;   a first voltage control unit for boosting gradually a voltage supplied from said main unit to said load voltage converter into said first voltage when an insertion operation to said main unit is performed without halting a power supply from said main unit;   a bypass line for bypassing said first voltage control unit and said load voltage converter to supply an electric power from said main unit to said second element; and   a diode connected to said bypass line.   
     
     
       10. A circuit mounting unit according to claim 9, wherein said first control unit comprises: a variable resistor that varies from a high resistance state thereof to a low resistance state thereof as a switching voltage externally added increases;   a switching voltage converter that converts an electric power from said main unit into said switching voltage to supply to said variable resistor; and   a capacitor inserted between an output terminal for said switching voltage of said switching voltage converter and a ground line,   said variable resistor in said first voltage control unit being connected to a power supply line from said main unit to said load voltage converter.   
     
     
       11. The circuit mounting unit according to claim 10, wherein said variable resistor in said first voltage control unit comprises an N-channel field effect transistor. 
     
     
       12. The circuit mounting unit according to claim 11, further comprising a resistor which is connected in parallel to said capacitor in said first voltage control unit. 
     
     
       13. The circuit mounting unit according to claim 12, wherein said variable resistor and said switching voltage converter which constitute said first voltage control unit are previously formed in an integrated circuit form. 
     
     
       14. The circuit mounting unit according to claim 11, wherein said variable resistor and said switching voltage converter which constitute said first voltage control unit are previously formed in an integrated circuit form. 
     
     
       15. The circuit mounting unit according to claim 10, further comprising a resistor which is connected in parallel to said capacitor in said first voltage control unit. 
     
     
       16. The circuit mounting unit according to claim 15, wherein said variable resistor and said switching voltage converter which constitute said first voltage control unit are previously formed in an integrated circuit form. 
     
     
       17. The circuit mounting unit according to claim 10, wherein said variable resistor and said switching voltage converter which constitute said first voltage control unit are previously formed in an integrated circuit form. 
     
     
       18. A circuit mounting unit, comprising: a first element connected to a main unit via a connector, driven by a first voltage which is supplied from said main unit;   a load voltage converter for converting said first voltage from said main unit into a second voltage different from said first voltage;   a second element driven by said second voltage converted by said load voltage converter;   a first voltage control unit for boosting gradually a voltage supplied from said main unit to said load voltage converter into said first voltage when an insertion operation to said main unit is performed without halting a power supply from said main unit;   a bypass line for bypassing said first voltage control unit and said load voltage converter to supply an electric power from said main unit to said second element;   a diode connected to said bypass line; and   a second voltage control unit for controlling to increase gradually a voltage sneaking from said main unit to said load voltage converter via said bypass line when said insertion operation is performed.   
     
     
       19. The circuit mounting unit according to claim 18, wherein said first control unit comprises: a variable resistor that varies from a high resistance state thereof to a low resistance state thereof as a switching voltage externally added increases;   a switching voltage converter that converts an electric power from said main unit into said switching voltage to supply to said variable resistor; and   a capacitor inserted between an output terminal for said switching voltage of said switching voltage converter and a ground line,   said variable resistor in said first voltage control unit being connected to a power supply line from said main unit to said load voltage converter.   
     
     
       20. The circuit mounting unit according to claim 19, wherein said variable resistor in said first voltage control unit comprises an N-channel field effect transistor. 
     
     
       21. The circuit mounting unit according to claim 19, further comprising a resistor which is connected in parallel to said capacitor in said first voltage control unit. 
     
     
       22. The circuit mounting unit according to claim 19, wherein said variable resistor and said switching voltage converter which constitute said first voltage control unit are previously formed in an integrated circuit form. 
     
     
       23. The circuit mounting unit according to claim 18, wherein said second voltage control unit comprises: a variable resistor that varies from a high resistance state thereof to a low resistance state thereof as a switching voltage externally added increases;   a switching voltage converter that converts an electric power obtained from said main unit via said diode into said switching voltage to supply to said variable resistor; and   a capacitor inserted between an output terminal for said switching voltage of said switching voltage converter and a ground line,   said variable resistor in said second voltage control unit being connected to a power supply line from said load voltage converter to said second element.   
     
     
       24. The circuit mounting unit according to claim 23, wherein said variable resistor in said second voltage control unit comprises an N-channel field effect transistor. 
     
     
       25. The circuit mounting unit according to claim 23, further comprising a resistor which is connected in parallel to said capacitor in said second voltage control unit. 
     
     
       26. The circuit mounting unit according to claim 23, wherein said variable resistor and said switching voltage converter which constitute said second voltage control unit are previously formed in an integrated circuit form.